Mineral oil composition



' Patented May 15, 1945 p John H. Bishop, Wenonah, N. J., assignor toSocony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporationof New York No Drawing. Application March 17,1942,

' Serial No. 435,077

6 Claims. (crass-41) This invention has to do with lubricants; and

is more particularly concerned with lubricants for ferrous metalsurfaces in anenvironment where such surfaces are also subject tocontact with water and in consequence are likely to rust.

As is well known to those familiar with the art. difficulties have beenexperienced during I118 operation of steam turbines, andparticularly'during the initial operation or new steam turbines, becauseof therusting of ferrous metal: 10

parts. The combination offresh (not previously .used) oil; clean, newmetal surfaces; and moist conditions of'operation of new steam turbinesappears particularly conducive to rusting dimeulties. Particles of rustformed on or carried to tne bearing -,surfaces of small clearance, suchas the governor, for example, tend to: cause sticking, which rendersthem inoperative. In

cases of severe rusting, bearings may be injured.

This rusting phenomenon under conditions or 6 the type outlined above isevidently theresult of improper or inadequate "wetting" of the metalsurfaces with oil, thus permitting a preferential contact of thesurfaces with the water which is present. One expedient used in the pastto prevent rusting. under these conditions has been to mix with the newoil several per cent of an oil which has been previously used in turbineoperation for a considerable period of cause the oil to -wet". moreadequately and better adhere to the metal surfaces. Such an expedient,however, not only introduces those.ox.-

ldation products'which protectagainst rusting The oxidation products inthe used oil 0.05% to'about 0.2% or in aniline dissulpnide. and fromabout 0.01% to about 0.1% ofdegras fatty acids, in a turbine oil willnotonly. prevent undue rusting of themetal parts of a new turbine,especiallynuring the break-in period, of a newturbine, when suchproblem. is most acute, out will, in, addition, increase the effectivelife .01 the oil composition. V

I am aware of the fact that it has been proposed, in U. S. Patent No.2,151,353, to use degras fatty acids in relatively large proportions of.from 5% to 20 %'in coating and drawing compositions.

The present invention distinguishes over the aforesaid disclosure in thediscovery that with the combination contemplated herein, a' jvery Ismall quantity-of the order of 0.10% or less of degras fatty acids maybe used to improve 4 t'urbineoils. I

.when'large quantities, such as'5% to 20%. (as

disclosed .in' the aforesaid patent), of degras fatty acids are used inturbine oils substantial combination with a minor proportion of ananiline disulphide in turbine oils, the emulsification tendencies, ofthe oil composition are substantially. reduced, so much so, in fact,that tne compositions contemplated herein are extremely efrectiv'e anddesirable for use in turbines. As small a quantity as 0.01% oftheliegras fatty acids may be used in the turbine oil compositions 1contemplated herein to obtain improvementin rust prevention andeffective life of the oils Thus.

and undesirable emulsif cation of the 'oil is caused. I have found,however, t at when not more than 0.10% of degras fatty acids is used inf i but iiftroducas as-well other oxidation products, 535 i bs t the uti y o germs fatty which promote the formation of sludge and acidf. V ah W be used In t in 11 c m vent rusting-have tlie undesirable propertyof .40 an upper. limit the neishbbrliwd Ora-19% positions contemplateddetermined by a lowejr'limit of about-0.01% below which effec v tiveanti-rustinz'properties are not obtained, and

ity and.increase emulsifying tendencies. other} materials such asstearic acid-have been pro- .posed; but such additives, although they dopreminor proportions of both an aniline disulphide I will prevent unduerusting of the metal parts.

" unduly raisin: theacidity (neutralizationnum ber, or N. N.) of the oiland of accelerating the development of acidity in use.

r The present invention is predicated ,upon the eral oil, 'such *as aturbine oil or the like, of

and dexras' fwool grease). fatty acids provides wetting of the metalsurfaces with the oil and This. new and'novel -combination of improvingagents in a turbine oil functions in several ways in that'it adequately"we the metal surfaces and inhibits the deleterious effects of'oxidationI upon the oil. The incorporation of from about 60 I above which theemulsion problem becomes too The'presevere for commercialpracticability. ferrewquantity of the desras fatty acids for the wpurpose of this invention is of the order ,of 0.93%. Y discovery thatthe admixture with'a viscous min- Broadly,-.this invention contemplatesthe incorporation, in the aforesaid turbine oil, ofdegr'as fattyacids'whichare obtained from. degra's,

a mixture of fatty acids,'fatty alcohols and fatty esters. Degras fattyacids may be prepared from degras by various means, and may be purchasedon the market. The fatty acids vary inneutral' ization .nuinberand it isbelieved that such vari-' ation is associated with the method ofpreparation andmay or may not be associated with differences in degrasitself. For example, typical degras fatty acids were prepared i thefollowing ways.

A specimen of wool grease was saponifled under pressure with alcoholicpotassium hydroxide.

The unsaponifiable material (fatty alcohols and. fattyesters)was-removed from the-soap mixture formed in the saponification step,with solvent. The fatty acids were recovered by acidifying the soapsolutionwith mineral acid and extracting with solvent. The fatty acidsthus ob- 0.03% of the fattyacids having an N. N. of from i tained'werefree of mineral acids and solvent,

and had a neutralization number (N. N.) of 163.

' A specimen of wool grease was saponifled under pressure with alcoholicpotassium hydroxide and with methyl ethyl ketone as a solvent. Theunsaponiilable material was removed with solvents, the fatty acids wererecovered from the soap soof aniline disulphide and representativedegras time. In some instances. as will appear from the 7 table below,the temperature was 140? F. .and in others it was 167 F. also, as willappear from the,

table, the time intervalwas 24 hours in some of the tests and in othersit was 48 hours. The mixture was agitated constantly by a motor drivenstirrer. The improving agents used inthe oil I samples tested areindicated by the abbreviations lution with a solvent afteracidification, and the I solvent was subsequently removed from the fattyacids. The fatty'acids. so obtained were free of mineral acid andsolvent, and had a neutralization number ranging from 86 to 147. Thefatty acids of lower N. N., from 86 to 110,. were less eflective inturbine oils than were those of higher N. N., from 110 ton-i7. 'Forexample; 0.02% to 110 to 147 gave perfect rust tests (des unease:

low); whereas tho'se fatty acids havin an N. N. of from 86' to 110,while effective anti-rustingagents,- were requiredin larger amountsto'pro- -duce' good results.

All degras fatty acids are effective for the pur poses of thisinvention, and particularly eifec-' tive-and preferred-are those fattyacids obtained from. degraswhich have a neutralization number of fromabout 110 to about 170. e In combination withthe degras fatty acidsinthe aforesaid turbine oils is an aniline disulphide,-

- that'is aniline'disulphide itself or an alkyl-sub stituted anilinedisulphide, which functions as an.

antioxidant.

The, aniline disulphides conteinplated hereinmay be represented by thegeneral A. D. S. (aniline' disulphide) and D. F. A. (degras fattyacids). The neutralization number (N. N.) of the degras, fatty acid usedis also indicated.

Table-II 20 r I P Per ondition Oil mpmvmg. cent oisteel agent I centwater l hrs. Spqqimens N'0ne 1.0 140 24 Rust. 11.1). 0.1 "1.0 140 24 Do;A.D. 0.13 1.0 140 24 Norust.

' D. F.A ...t 0:1

iN.l\.=l63) I r A .D.S 0.l 1.0 140 24 Do. D; F. 0,02 1 N. N.=l63) 1 L A-1118 0.1 10.0 107 48 Do. s llfilfimifi) 0.02 A 3 a v 11..-... D.S 0:110.0 167 (24) D'o. 0.01 y 48) .130.

s 10.0 107 48 Bust.

10. 0 167 48 Do. 10.0 167 48 No rust.

' disulphide and degras fatty acids to inhibit the wherein, R and R" areselected from the group consisting" of hydrogen and aliQl radicals.

The oil used in the composition hereinb'efore r describbd maybe of thetype normally used for the lubrication of turbines. In general,

the oil may be defined as a viscous mineral oil 1 iron 100 to. 600seconds at 100 Fi- Typical tut- .bine oils with which a hnixture of ananiline di- I To the efl icacy of the combination 'e disulphide anddegras fatty acids in turbine oils-typical turbine oil compositions.fractionhaving'a Sgybolt'Universal viscosity of deleterious effects ofoxidation upon turbine oils is shown by the results-of the followingBrown- 'Boveri. oxidation teststabulatedbelow in Table 3 III. A typicalturbine 0Q coinpiosition, as contemplated by the present "invention,comprising oil A, 0.1% ofaniline disulphide and 0.02% of degras fattyacids (N. N. =l63), was compared with an oil composition-comprising oilA and-0. 1%, of aniline disulphide. That the oxidation characteristicsof the oil were only slightly changed by the addition of degrasfattyacids is evident from the results given in Table 1 Tabieru on f ggg a. eent l m N.N. Sludge A A.D.S. 0.1 15 0.03 3

A.D.S.- 0.1 24- .0.05 .1 3- D. F, A 0.02

From the foregoin'git will be seen that minor .moportionsof an anilinedisulphide and degras;

fatty acids in turbine oils will provide lubricants which may be used=efl'ectively in the presence of moisture to prevent rusting of ferrousmetalparts L followingspeciflcations; e I

- eu urn. Q -28.4 22a .ate. 1 5 g 9 385 420 g'iflgsgr i 1 1% its-15s 001t. moi. "84.5 250.5 43 01 -.2

oil. A and B and very small: amounts by the moisturev present, and toprevent changes in the oxidation characteristics ofsuch oils in such anenvironment. It is to beunderstood that although we have hereindescrilkd and illustrated the invention with certain preferred mineraloil.- blends, the invention is not restricted to the specific examplesgiven but includes within its scope whatever changes fairly comewithmthe spirit oftheappendedclaims.

consisting aniline disulphide m; alkyl-substl- Iclaiin:

1. An-oil composition adapted for the lubrication of ferrous metalsurfaces in an environment containing water, comprising aviscous mineraloil having in admixture therewith a minor proportion, from about 0.01%to about 0.1%, of degras fatty acids and a minor. proportion, from about0.05% to about 0.2%, of a compound "selectedfrom the group, consistingoi aniline disulphide and alkyl-substituted aniline disulphides.

2. An oil composition adapted for the lubrication of ferrous metalsurfaces in an environment containing water, comprising a viscousmineral 'oilhaving in admixture therewith a minor proportion; about0.03%, of degrasjatty acids and a minor proportion, from about 0.05% toabout 0.2%, of a compound selected from the group consisting of anilinedisulphide and alkyl-substi-" tuted aniline disulphides. r

3. An oil composition adapted for the lubrication of ferrous metalsurfaces in an environment containing water, comprising a viscous--mineral oil having in admixture therewith a minor proportion, fromabout 0.01% to about 0.1%, of .degras-fatty acids having aneutralization number of from about 110 to 170, an'd a.

minor proportion, from about 0.05% to about 0.2%, of a compound selected:Irom the grouptuted aniline disulphides.

4. An oil composition adapted for the lubrication of ferrous metalsurfaces in an environment containing'water, comprising a viscousmineral oil having in admixture therewith a minor pro- -porti0n,'. fromabout 0.01% to about 0.1%,of

degras fatty acids having a neutralization-number of from about 110 toabout 170, and a minor proportion, from about 0.05% to about 0.2%, of

aniline disulphide.

5. A turbine oilcomposition comprising a mineral oil fraction having aSaybolt Universal viscosity of from 100 seconds to 600 seconds at 100.-tion of ferrous metal surfaces in an environmentcontaining water,comprising a viscous mineral oil having in admixture'therewith about0.03%v 'of degras fatty acidsfand about 0.1% of aniline.

F. and having in admixture therewith a minor proportion, from about0.01% to about 0.1%,. of degras fatty acids and a minor proportion, fromabout 0.05% to about 0.2%, of a compound selected from the groupconsisting of aniline disul-.

'phide and alkyl-substituted aniline disulphides.

*6. An oil compositiomadapted for the lubricadisulfide.

JOHN H. BISHOP.

